The disclosure herein relates to an image forming apparatus for forming images on sheets.
An image forming apparatus which uses liquid developer is known as a device for forming an image on a sheet. This type of image forming apparatuses typically has a fixing device configured to fix images onto sheets. The fixing device generates high heat in order to melt toner contained in the liquid developer, which is transferred onto the sheet.
It is not necessary for a fixing device to generate heat if the fixing device uses liquid developer which has characteristics such that its components (carrier solution) permeate into a sheet and high-molecular compounds with dispersed pigment therein deposit on the surface of the sheet. However, the present inventors discovered disadvantageous properties which are likely to cause peel-off of an image formed on the sheet by means of such liquid developer.
The inventors of the present application proposed a non-thermal fixing method for preventing peel-off of an image from a sheet. According to researches of the inventor, if an image formed with the liquid developer is rubbed on a sheet, the image is less likely to be peeled off from the sheet. According to various researches of the inventors, as a time period for rubbing an image increases, a fixation ratio of the image on a sheet increases. In addition, as a number of rubbing directions on a sheet increases, the fixation ratio of an image on the sheet increases.
An increase in the rubbing level for an image contributes to improving a fixation ratio of the image whereas excessive rubbing may adversely interfere with conveyance of a sheet. In view of the aforementioned findings, the excessive rubbing to an image may cause various drawbacks such as jam, wrinkles or damages of sheets.
An object of the disclosure is to provide an image forming apparatus which achieves a high fixation ratio under an appropriate rubbing condition.